ABSTRACT
IntroductionFor the appropriate allocation of medical resources to at-risk COVID-19 patients, a simple risk scoring model for the risk stratification of clinical deterioration in the early stage of symptom onset would be invaluable. Here, we report the development and validation of such a model for clinical deterioration in COVID-19.MethodsThis multicenter retrospective cohort study conducted in Japan included adult patients (≥18 years old) with confirmed COVID-19 according to molecular diagnostic methods and hospitalized in two hospitals. Patients who did not undergo laboratory tests within 10 days of initial symptom onset and those who were treated with oxygen therapy before hospitalization were excluded. Patients were divided into derivation (n=446) and temporal validation (n=305) datasets based on hospitalization period. The primary outcome was need for oxygen therapy within 14 days of hospitalization.ResultsA novel ABCD Risk Score (range, 0–12) comprising age, body mass index, C-reactive protein, and lactate dehydrogenase levels at admission was developed in the derivation dataset. This risk score showed good discrimination for clinical deterioration (concordance statistics, 0.86; 95% confidence interval [CI]: 0.72–0.90) with good calibration (intercept, 0.01; slope, 0.99) in the temporal validation dataset. Three risk groups were defined: low risk (≤3 points), intermediate risk (4–6 points), and high risk (≥7 points). In the validation dataset, the clinical deterioration rates for these three groups were 7.1% (95% CI: 3.1%–13.6%), 32.9% (95% CI: 22.3%–44.9%), and 73.3% (95% CI: 64.5%–81.0%), respectively. The risk score showed better discrimination and calibration performance than four previously reported risk scoring models.ConclusionOur novel ABCD Risk Score can be used for the risk stratification of clinical deterioration in COVID-19 patients at an early stage of symptom onset.
Subject(s)
COVID-19ABSTRACT
A high-throughput, fully automated antigen detection test for SARS-CoV-2 is a viable alternative to reverse transcription polymerase chain reaction (RT-qPCR) for mass screening during outbreaks. In this study, we compared RT-qPCR for viral load and the VITROS® SARS-CoV-2 Antigen Test with reference to the results of the LUMIPULSE® SARS-CoV-2 Ag Test. Of 128 nasopharyngeal swab specimens taken from patients suspected of being infected with SARS-CoV-2, 49 were positive and 79 were negative according to RT-qPCR. Consistent dose-dependent detection with VITROS® assay was successfully achieved when using nasopharyngeal swab specimens with Ct values of ≤32.0, whereas the CLEIA-based the LUMIPULSE® assay was able to detect lower viral loads compared with the VITROS® assay. Our results show that the performance of the VITROS® assay was satisfactory for the diagnosis of contagious COVID-19 patients in the clinical setting.
Subject(s)
COVID-19ABSTRACT
Background: We analyzed antibody response patterns according to level of disease severity in patients with novel coronavirus disease 2019 (COVID-19) in Japan. Methods: We analyzed 611 serum specimens from 231 patients with COVID-19 (mild, 170; severe, 31; critical, 30). IgM and IgG antibodies against nucleocapsid protein (N) and spike 1 protein (S1) were detected by enzyme-linked immunosorbent assays. Findings: The peaks of fitting curves for the OD values of IgM and IgG antibodies against N appeared simultaneously, while those against S1 were delayed compared with N. The OD values of IgM against N and IgG against both N and S1 were significantly higher in the severe and critical cases than in the mild cases at 11 days after symptom onset. The seroconversion rates of IgG were higher than those of IgM against both N and S1 during the clinical course based on the optimal cut-off values defined in this study. The seroconversion rates of IgG and IgM against N and S1 were higher in the severe and critical cases than in the mild cases. Conclusion: Our findings show that a stronger antibody response occurred in COVID-19 patients with greater disease severity and there were low seroconversion rates of antibodies against N and S1 in the mild cases. The antibody response patterns in our population suggest a second infection pattern, leading us to hypothesize that cross-reactivity occurs between SARS-CoV-2 and past infection with other human coronaviruses.
Subject(s)
COVID-19ABSTRACT
BackgroundWe evaluated clinical characteristics and the clinical utility of VITROS SARS-CoV-2 antibody tests according to COVID-19 severity in patients in Japan. MethodsWe analyzed 255 serum specimens from 130 COVID-19 patients and examined clinical records and laboratory data. Presence of total (IgA, IgM, and IgG) and specific IgG antibody for the spike 1 antigen of SARS-CoV2 was determined using VITROS Anti-SARS-CoV-2 antibody tests. FindingsOverall, 98 (75.4%) and 32 (24.6%) patients had mild and severe COVID-19, respectively. On admission, 76 (58.5%) and 45 (34.6%) patients were positive for total and IgG antibody assays. Among 91 patients at discharge, 90 (98.9%) and 81 (89.0%) patients were positive for total and IgG antibody, respectively. Clinical background and laboratory findings on admission, but not the prevalence or concentration of total or IgG antibody, were associated with disease prognosis. Total and IgG antibody intensity were significantly higher in severe cases than in mild cases in serum collected after 11 days from onset, but not within 10 days. ConclusionVITROS Anti-SARS-CoV-2 Total and IgG assays will be useful as supporting diagnostic and surveillance tools and for evaluation of humoral immune response to COVID-19. Clinical background and laboratory findings are preferable predictors of disease prognosis.
Subject(s)
COVID-19ABSTRACT
Background: We evaluated the clinical performance of an immunochromatographic (IC) IgM/IgG antibody assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) and chest computed tomography (CT) for the diagnosis of Coronavirus disease 2019 (COVID-19). Methods: We examined 139 serum specimens collected from 112 patients with COVID-19 and 48 serum specimens collected from 48 non-COVID-19 patients. The presence of IgM/IgG antibody for SARS-CoV2 was determined using the One Step Novel Coronavirus (COVID-19) IgM/IgG Antibody Test. Chest CT was performed in COVID-19 patients on admission. Findings: Of the 139 COVID-19 serum specimens, IgM was detected in 27.8%, 48.0%, and 95.8% of the specimens collected within 1 week, 1-2 weeks, and >2 weeks after symptom onset and IgG was detected in 3.3%, 8.0%, and 62.5%, respectively. Among the 48 non-COVID-19 serum specimens, 1 generated a false-positive result for IgM. Thirty-eight of the 112 COVID-19 patients were asymptomatic, of whom 15 were positive for IgM, and 74 were symptomatic, of whom 22 were positive for IgM and 7 were positive for IgG. The diagnostic sensitivity of CT scan alone and in combination with the IC assay was 57.9 % (22/38) and 68.4% (26/38) for the asymptomatic patients and 74.3% (55/74) and 82.4% (61/74) for the symptomatic patients, respectively. Conclusion: The IC assay had low sensitivity during the early phase of infection, and thus IC assay alone is not recommended for initial diagnostic testing for COVID-19. If RT-qPCR is not available, the combination of chest CT and IC assay may be useful for diagnosing COVID-19.